Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/lib/Drupal/Component/Plugin/PluginManagerInterface.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * @file
+ * Contains \Drupal\Component\Plugin\PluginManagerInterface.
+ */
+
+namespace Drupal\Component\Plugin;
+
+use Drupal\Component\Plugin\Discovery\DiscoveryInterface;
+use Drupal\Component\Plugin\Factory\FactoryInterface;
+use Drupal\Component\Plugin\Mapper\MapperInterface;
+
+/**
+ * Interface implemented by plugin managers.
+ *
+ * There are no explicit methods on the manager interface. Instead plugin
+ * managers broker the interactions of the different plugin components, and
+ * therefore, must implement each component interface, which is enforced by
+ * this interface extending all of the component ones.
+ *
+ * While a plugin manager may directly implement these interface methods with
+ * custom logic, it is expected to be more common for plugin managers to proxy
+ * the method invocations to the respective components, and directly implement
+ * only the additional functionality needed by the specific pluggable system.
+ * To follow this pattern, plugin managers can extend from the PluginManagerBase
+ * class, which contains the proxying logic.
+ *
+ * @see \Drupal\Component\Plugin\PluginManagerBase
+ *
+ * @ingroup plugin_api
+ */
+interface PluginManagerInterface extends DiscoveryInterface, FactoryInterface, MapperInterface {
+}